was already more than either of them have accomplished.
I'm sure they have accomplished more important things than college!
When I started high school I was never taught to be the perfect model student, nor was I taught ---maybe you really were raised by slackers, but this all sounds like you are blaming your own shortcomings on your parents. It is better to take responsibility.
22 and still be living at home like my brother. --- you seem so judgmental! This is not the right approach. You have to give an intellectual discussion of an academic or professional aspiration... something important to you. Whatever you want to do in the world has to start with a degree, so talk about this program as a stepping stone on your path.
The years flash by. You are getting ready to do your career now, so what is it going to be? Whatever that is all about... choose an event from your past that demonstrates or represents this ambition you have, and it is that ambition that provides the energy you can contribute at this school.
Your contribution depends on a particular intellectual interest, so write about an event related to your biggest academic or career interest.
:-)